In this paper, we analyze the application of combined Chinese formula, and by adopting the philosophy of TCM, argue that its philosophical source is parallelism between prescription and syndrome, which embodies the TCM philosophy thought of image-numerology and intuition. Combined Chinese formula is based on pathogenesis of disease, pathogenesis condition, aims to improve efficiency, and embodies unity thinking, neutral thinking, changing thinking and function thinking of TCM. The application of combined Chinese formula came into being on the basis of philosophical thought of TCM; meanwhile it reflects the clinical application of the philosophical thought of TCM.